Cochlear electrode array

ABSTRACT

An implantable tissue-stimulating prosthesis such as a cochlear implant system comprising an elongate carrier member having a distal end, a proximal end, and at least one electrode positioned thereon; at least one electrical conductor extending from one or more of the at least one electrode; a lead extending from the carrier member and enclosing the at least one electrical conductor; and a holding member constructed and arranged to radially extend outwardly from the surface of the carrier member to facilitate grasping of the holding member during implantation of the carrier member in a patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Australian Provisional PatentApplication No. 2003901852, entitled “Cochlear electrode array,” filedon Apr. 16, 2003. The entire disclosures and contents of the aboveapplication are hereby incorporated by reference. This application isrelated to International Application No. PCT/AU03/00229 and U.S. Pat.Nos. 4,532,930, 6,537,200, 6,565,503, 6,575,894, and 6,697,674. Theentire disclosure and contents of the above applications are herebyincorporated by reference.

BACKGROUND

1. Field of the Invention

The present invention relates generally to a tissue-stimulatingprosthesis and, more particularly, to an electrode carrier member forsuch a prosthesis.

2. Related Art

Delivery of electrical stimulation to appropriate locations within thebody may be used for a variety of purposes. For example, functionelectrical stimulation (FES) systems may be used to deliver electricalpulses to certain muscles of a recipient to cause a controlled movementof the limb of such a recipient.

As another example, electrical stimulation of the cochlea using cochlearimplant systems may also be used to directly deliver electricalstimulation to the auditory nerve fibers, thereby allowing the brain toperceive a hearing sensation resembling the natural hearing sensationnormally delivered to the auditory nerve.

Cochlear implant systems typically have two primary components: anexternal component commonly referred to as a control unit, and animplanted component commonly reffered to as a receiver/stimulator unit.Traditionally, both of these components cooperate with each othertogether to provide the sound sensation to a recipient.

The external component has traditionally included a microphone thatdetects sounds, such as speech and environmental sounds, a speechprocessor that selects and converts certain detected sounds,particularly speech, into a coded signal, a power source such as abattery, and an external transmitter antenna.

The coded signal output by the speech processor is transmittedtranscutaneously to the implanted receiver/stimulator unit locatedwithin a recess of the temporal bone of the recipient. Thistranscutaneous transmission occurs via the external transmitter antennawhich is positioned to communicate with an implanted receiver antennaprovided with the receiver/stimlator unit. This communication transmitsthe coded sound signal while also providing power to the implantedreceiver/stimulator unit. Conventionally, this link has been in the formof a radio frequency (RF) link, but other such links have been proposedand implemented with varying degrees of success.

The implanted receiver/stimulator unit traditionally includes the notedreceiver antenna that receives the coded signal and power from theexternal processor component. The implanted unit also includes astimulator that processes the coded signal and outputs a stimulationsignal to an intracochlear electrode assembly mounted to a carriermember which applies the electrical stimulation directly to the auditorynerve producing a hearing sensation corresponding to the originaldetected sound.

To position the carrier member that is mounting the electrode assembly,a surgeon typically forms a cochleostomy before gripping the member byhand or with a tool and then inserting a leading end of the carriermember through the cochleostomy and into preferably the scala tympani ofthe cochlea.

One potential problem during the insertion process is the potential forthe carrier member to be damaged and/or rendered at least partiallyinoperative due to the handling the member receives prior to and duringthe insertion procedure.

SUMMARY

In one aspect of the invention, an implantable tissue-stimulatingprosthesis is disclosed. The prosthesis comprises: an elongate carriermember having a distal end, a proximal end, and at least one electrodepositioned thereon; at least one electrical conductor extending from oneor more of the at least one electrode; a lead extending from the carriermember and enclosing the at least one electrical conductor; and aholding member constructed and arranged to radially extend outwardlyfrom the surface of the carrier member to facilitate grasping of theholding member during implantation of the carrier member in a patient.

In another aspect of the invention, a cochlear implant system isdisclosed. The cochlear implant system comprises: a stimulator unit; anelongate carrier member having a distal end, a proximal end, and amultichannel electrode array positioned at the distal end thereof forimplantation in the cochlear of a person; a plurality of electricalconduction means electrically coupling each electrode of the electrodearray to the stimulator unit; and a holding member constructed andarranged to radially extend outwardly from the surface of the carriermember.

In a further aspect of the invention, a carrier member for use in atissue-stimulating prosthesis is disclosed. The carrier membercomprises: an elongate carrier member body having a distal end, aproximal end and a holding member radially extending outwardly from thesurface of the carrier member body; an electrode array disposed at thedistal end of the carrier member body; and means for communicatingsignals from a stimulator unit to the electrode array.

In a still further aspect of the invention, a method of implanting atissue-stimulating prosthesis in a desired location in a recipient isdisclosed. The method comprises: providing an elongate carrier membercomprising a holding member extending from a surface thereof, electrodesdisposed at a distal end thereof, and electrical conductors connected tothe electrodes and extending through the carrier member from the distalto proximal end thereof; forming a cochleostomy, gripping the holdingmember; and inserting a substantially straight carrier member throughthe cochleostomy and into the cochlea.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary cochlear implant systemsuitable for implementing embodiments of the present invention.

FIG. 2 is a perspective view of one embodiment of a carrier memberaccording to the present invention.

FIG. 3A is longitudinal a cross-sectional view of the carrier memberillustrated in FIG. 2.

FIG. 3B is a lateral cross-sectional view of the carrier memberillustrated in FIG. 2.

FIG. 4 is a perspective view of a carrier member implantation tubeaccording to one embodiment of the present invention.

FIG. 5 is a perspective view of a insertion tool cartridge with theembodiment of the carrier member illustrated in FIG. 2 inserted therein.

DETAILED DESCRIPTION

Embodiments of the present invention are directed to an apparatus andmethod for facilitating implantation of a medical device into a patient.Embodiments of the present invention are described below in connectionwith one type of medical device, a cochlear prosthetic device. Cochlearprostheses use direct electrical stimulation of auditory nerve cells tobypass absent or defective hair cells that normally transducer acousticvibrations into neural activity. Such devices generally usemulti-contact electrodes inserted into the scala tympani of the cochleaso that the electrodes may differentially activate auditory neurons thatnormally encode differential pitches of sound. Such devices are alsoused to treat a smaller number of patients with bilateral degenerationof the auditory nerve. For such patients, the cochlear prosthetic deviceprovides stimulation of the cochlear nucleus in the brainstem.

Exemplary cochlear prostheses in which the present invention may beimplemented include, but are not limited to, those systems described inU.S. Pat. Nos. 4,532,930, 6,537,200, 6,565,503, 6,575,894 and 6,697,674,the entire contents and disclosures of which are hereby incorporated byreference herein. As described therein, cochlear prostheses generallyinclude an external, wearable control unit that determines a pattern ofelectrical stimulation that is provided to an implanted stimulator unitcontaining active circuitry in a hermetic enclosure. Electricalstimulation channels are routed through electrodes to provide electricalstimulation of auditory nerve cells.

FIG. 1 is a schematic diagram of an exemplary cochlear implant system orprosthetic device 100 in which embodiments of the present invention maybe implemented. In the context of such an application, embodiments ofthe present invention are directed to a carrier member of an electrodearray 104 which has a holding member disposed on the surface thereof forthe surgeon to grasp during insertion or implantation of the electrodearray into the cochlear 122 of a recipient (also referred to herein as apatient).

Once implanted, electrodes 102 of the electrode array 104 receivestimulation signals from a stimulator unit 106. Stimulator unit 106 istypically electrically connected to electrode array 104 by way ofelectrical lead 108. Lead 108 is preferably continuous with noelectrical connectors external the housing of stimulator unit 106.

Stimulator unit 106 is preferably positioned within a housing that isimplantable within the patient. The housing for stimulator unit 106 istypically implantable within a recess in the bone behind the earposterior to the mastoid. When implanted, the housing preferablycontains, in addition to stimulator unit 106, a receiver unit 110.Receiver unit 110 is preferably adapted to receive signals 114 from acontroller 112. Controller 112 is, in use, preferably mounted externalto the body behind the outer ear 120 of the patient such that signals114 are transmitted transcutaneously through the skin of the patient.

Signals 114 travel from controller 112 to receiver unit 110 and viceversa. Receiver unit 110 includes a receiver antenna, such as an antennacoil, adapted to receive radio frequency (RF) signals from acorresponding transmitter antenna 116, such as an antenna coil, wornexternally of the body. The radio frequency signals may comprisefrequency modulated (FM) signals. It should be appreciated that thereceiver antenna may also transmit signals, and that the transmitterantenna may receive such signals. The transmitter antenna coil ispreferably held in position adjacent the implanted location of thereceiver antenna coil by way of respective attractive magnets (notshown) mounted centrally in, or at some other position relative to, thecoils.

External controller 112 comprises a speech processor (not shown) adaptedto receive signals output by a microphone 118. During use, microphone118 is preferably worn on the pinna of the recipient, however, othersuitable locations may be envisaged, such as a lapel of the recipient'sclothing. The speech processor encodes the sound detected by microphone118 into a sequence of electrical stimuli in accordance with speechcoding stratagies now or later developed for cochlear implant systems.The encoded sequence is transferred to the implanted receiver/stimulatorunit using the transmitter and receiver antennae. The implantedreceiver/stimulator unit demodulates the signals and allocates theelectrical pulses to the appropriate electrode 102 by an algorithm whichis consistent with the chosen speech coding strategy.

External controller 112 may further comprise a power supply (not shown).The power supply may comprise one or more rechargeable batteries. Thetransmitter and receiver antennae are used to provide power viatranscutaneous induction to the implanted reciever/stimulator unit andthe electrode array.

While cochlear implant system 100 is described as having externalcomponents, in another embodiment, the controller, including themicrophone, speech processor and power supply may also be implantable.In such embodiments, the controller may be contained within ahermetically sealed housing or the housing used for stimulator unit 106.

It should be appreciated that although embodiments of the presentinvention are described herein in connection with cochlear prostheticdevice 100, the same or other embodiments of the present invention maybe implemented in other tissue-stimulating prosthetic devices as well.Examples of such devices include, but are not limited to, other sensoryprosthetic devices, neural prosthetic devices, and functional electricalstimulation (FES) systems. In sensory prostheses, information iscollected by electronic sensors and delivered directly to the nervoussystem by electrical stimulation of pathways in or leading to the partsof the brain that normally process a given sensory modality. Neuralprostheses are clinical applications of neural control interfaceswhereby information is exchanged between neural and electronic circuits.FES devices are used to directly stimulate tissue having contractilecells to produce a controlled contraction of the same.

FIG. 2 is a perspective view of a carrier member 200 in accordance withone embodiment of the present invention. FIG. 3A is a longitudinalcross-sectional view of the carrier member shown in FIG. 2 taken alongsectional line 3A-3A. FIG. 3B is a lateral cross-sectional view of thecarrier member shown in FIG. 2 taken along sectional line 3B-3B. Carriermember 200, as noted, may be a component of a cochlear implant systemsuch as cochlear implant system 100 illustrated in FIG. 1.

Carrier member 200 has an elongate body 202 having a proximal end 206and a distal end 222. At least one electrode 204 is mounted or otherwisepositioned at distal end 222 of carrier member body 202. In FIG. 2, aplurality of electrodes 204 is disposed on carrier member 202 to form anelectrode array 205. In one embodiment, electrodes 204 are arranged in alongitudinal array. An electrical connection is made between electrodes204 and stimulator unit 106 (FIG. 1) through lead 208 that extends outof carrier member body 202 near its proximal end 206. Lead 208 enclosesat least one electrical conductor extending from each electrode 204 tostimulate unit 106. Such conductors, which are typically in the form ofwires, are preferably formed from a suitable electrically-conductingmetal. Preferably, the conductors are formed from a suitablebiocompatible electrically-conducting material. It should be appreciatedthat other suitable electrically-conductive materials for use asconductive pathways through carrier member 200 may be used. For example,in alternative embodiments, semi-conducting materials andelectrically-conducting polymers are used.

Disposed on an exterior surface of carrier member body 202 is a holdingmember 212. Holding member 212 extends radially outward from theexterior surface of carrier member body 202 and is configured to beheld, grasped or otherwise utilized to control carrier member 200 duringplacement of the carrier member in a recipient.

In this illustrative embodiment, holding member 212 extendslongitudinally along a region of carrier member body 202. In oneembodiment, holding member 212 is positioned near proximal end 206 ofcarrier member body 202. It should be appreciated, however, that holdingmember 212 may be positioned at other locations on carrier member body202. For example, in one alternative embodiment, holding member 212 ispositioned closer to distal end 222 of carrier member 200.

Holding member 212 extends outwardly for a distance 218 defining theheight of the holding member. In one embodiment, height 218 of holdingmember 212 is slightly greater than width 304 (FIG. 3B) of carriermember body 202. It should be appreciated, however, that height 218 ofholding member 212 may vary along the length of holding member 212, withthe variable height defining regions of holding member 212. It shouldfurther be appreciated that the height of each such region of holdingmember 212 may be less than, greater than, or approximately equal towidth 304 of carrier member body 202.

As best shown in FIG. 3B, holding member 212 has two sidewalls 302A,302B (collectively and generally referred to as side wall(s) 302). Inthe illustrative embodiment, the cross-sectional shape of holding member212 has a region 3 12A in which sidewalls 302 are substantially parallelwith each other. Holding member 212 tapers in width 306 for a portion ofits height 218 away from body 202 of carrier member 200, defining atapered region 312B. In one embodiment, vertical region 310A constitutesbetween about 20% and 80% of height 218 of holding member 212. In onepreferred embodiment, vertical region 312A constitutes anywhere betweenabout 40% and 60% of height 218 of holding member 212. In a furtherembodiment, vertical region 312A constitutes approximately 50% of height218 of holding member 212. It should be appreciated by those of ordinaryskill in the art that in such a region 312A, sidewalls 302 of holdingmember 212 may be substantially parallel or parallel.

As one of ordinary skill in the art would appreciate, holding member 212may have a number of different cross-sectional shapes. For example, inone embodiment, along one or more longitudinal regions of holding member212, width 306 is contoured or has other cross-sectional configurationsto facilitate a particular objective such as facilitating a secure graspof holding member 212 manually or with a particular instrument. In oneembodiment, holding member 212 has a curved upper surface.

In one embodiment, carrier member 200 further comprises a support member214 that connects holding member 212 to body 202 of carrier member 200.Support member 214 may be connected to holding member 214 and carriermember body 202 using any attachment means now or later developed.Alternatively, holding member 212, support member 214 and carrier memberbody 202 are unitary. Support member 214 is an elongate member having alength 220 that is approximately equal to the maximum length 224 ofholding member 212. In the embodiment shown in FIGS. 2 and 3A, supportmember 214 is slightly longer than holding member 212 to support theconnection of lead 208. Support member 214 has, in certain embodiments,a width 308 that is less than the maximum width 306 of holding member212. It should be appreciated, however, that the dimensions andconfiguration of support member 214 may vary to satisfy the requirementsof the application and/or user. In one embodiment, support member 214acts as a support rail and functions in a manner described below.

In the embodiment shown in FIGS. 2, 3A and 3B, holding member 212 isformed integrally with body 202 of carrier member 200. In anotherembodiment, holding member 212 is formed separately to carrier member200 and then joined to the carrier member. In a further embodiment,holding member 212 may be removably or non-removably joined to carriermember 200. In yet other embodiments, holding member 212 may be mountedto carrier member 200 such that the relative position and orientation ofholding member 212 may be adjusted to accommodate particular users andapplications. Such alternative embodiments are described below.

As depicted in FIGS. 2 and 3A, lead 208 extends from carrier member 200.As noted, lead 208 contains at least one connector that extends fromelectrodes 204 back through body 202 and then to stimulator unit 106.Lead 208 is positioned such that wires passing therethrough do not passthrough holding member 212. As such, carrier member 200 may becontrolled by grasped holding member 212 without risk of damaging therelatively fine wires that are passing through body 202 of carriermember 200 and into lead 208.

While the depicted holding member 212 is a solid member, the holdingmember could be at least partially hollow or filled with a substancethat is different than the substance used to form sidewalls 302 ofholding member 212. For example, in one embodiment holding member 212has a cavity filled with air. Carrier member 200 may be formed from asuitable biocompatible material that has sufficient flexibility for theparticular application. In one embodiment, the biocompatible materialmay be a silicone, such as a flexible silicone elastomer-Silastic.Silastic MDX 4-4210 is an example of one suitable silicone for use inthe formation of the elongate member. In another embodiment, elongatecarrier member 200 may be formed from a polyurethane or similarmaterial.

As noted, holding member 212 may be mounted to carrier member 200 suchthat the relative position and orientation of holding member 212 may beadjusted. Such embodiments are described next below in connection withthe embodiments shown in FIG. 4. In the alternative embodimentillustrated in FIG. 4, a carrier member tube 400 is shown. In oneembodiment, carrier member tube 400 has a lumen 401 configured toreceive a conventional carrier member (not shown). In an alternativeembodiment, carrier member tube 400 is the outer casing or housing of acarrier member.

Carrier member tube 400 has at least one slot 402 that extendssubstantially parallel to the longitudinal axis of carrier member body202. Carrier member tube 400 may also have at least one slot 404 thatextends laterally around the circumference of the tube. For ease ofillustration and description, carrier tube 400 is shown to have onelongitudinal slot 402 and one lateral slot 404. In this embodiment, aholding member 408 has an extension arm 410 with a shaft 412 and aretaining member 414 that releasably retains holding member 408 adjacentto tube 400 in slots 402, 404.

Specifically, extension arm 410 is adjustable to secure or releaseholding member 408 to tube 400. When extension arm 410 is in a positionclosest to holding member 408, retaining member 414 compresses the wallof tube 400 against holding member 408 to maintain holding member 408 ina stationary position during use. Conversely, when extension arm 410 isin a position farthest from holding member 408, retaining member 414releases the wall of tube 400 enabling a user to reposition holdingmember 408 along longitudinal slot 402, as shown by arrow 416, and/oralong lateral slot 404, as shown by arrow 418. In addition to adjustingholding member 408 to a desired location in slots 404, 402, holdingmember 408 may also be rotated to about an axis 422, as shown by arrow420. In operation, holding member 212 may be translated around thecircumferences of carrier member 200 to a desired position that suitsthe surgeon implanting the prosthesis. Still further, holding member 212may be slidably mounted to carrier member 200 and so be adjustable inposition along at least a portion of the length of the carrier member.

In this particular embodiment, holding member 408 may be removed fromcarrier member tube 400 by positioning holding member 408 at theintersection of longitudinal slot 402 and lateral slot 404, and aligningthe extension arms of retaining member 414 with the slots 402 and 404.

It should be appreciated by those of ordinary skill in the art that theabove adjustability, rotatability and removability of holding member 408may be incorporated into the embodiments described above in connectionwith FIGS. 2 and 3A-3B. In one such embodiment, for example, tube 400 isthe exterior wall of carrier member body 202. It should also beappreciated that any combination of one or more of these features may beimplemented independently of each other.

As one of ordinary skill in the art would find apparent, techniquesother than extension arm 410 may be implemented to releasably retainholding members 212, 408 to carrier member 200 or carrier member tube400, respectively. For example, support member 214 may be configured toserve as a support rail that either extends through slots similar toslots 402, 404, or which is stationary and on which holding members 212,408 are slidingly attached.

In accordance with one embodiment, holding member 212, 408 has some formof indicia that identifies the location of the holding member on carriermember 200 or carrier member tube 400. Such indicia, which mayfacilitate the implantation of a carrier member in the cochlea of apatient, is described below in connection with the embodiments describedabove in reference to FIGS. 2-3B. A surgeon using carrier member 200 maybe informed by advice provided on the packaging or the like to note theposition of holding member 212.

In one embodiment, the indicia may be the shape of holding member 212.For example, the shape of holding member 212 may be clearly differentthan the shape of the remainder of carrier member 200. In anotherembodiment, such indicia may be the color of at least a part of andpreferably the entire surface of holding member 212. For example, thecolor of holding member 212 may be different than the color of carriermember body 202. In one specific embodiment, for example, holding member212 is white in color whereas carrier member 200 may have a differentcolor or indeed be essentially colorless due to the carrier member beingformed from a translucent or transparent material, such as a silicone.

It should be appreciated by those of ordinary skill in the art that incertain embodiments that the color may be applied to holding member 212or may be an inherent feature of the material selected to form theholding member. In one embodiment, a suitable filler, such as whitetitanium dioxide, may be mixed with a suitable silicone to form aholding member 212 that is approximately white in color.

In a still further embodiment, the indicia may include the tactility ofholding member 212 in comparison to the tactility of the remainder ofcarrier member 200. This difference in feel may be achieved throughvarious techniques now or later developed, such as the selection of amaterial that comprising at least part of holding member 212. Forexample, in one embodiment, holding member 212 is formed from a plasticmaterial such as polypropylene while carrier member 200 is formed from asuitable biocompatible material such as silicone. In such an embodiment,holding member 212 will have a different tactility to that of a carriermember 200.

In another embodiment, the surface finish of holding member 212 may bedifferent to that of the surface finish of carrier member 200. Forexample, undulations or channels formed in holding member 212 wouldpresent a different tactility to the normally relatively smooth finishof the surface of carrier member 200.

It will be appreciated that holding member 212 could have two or more ofthe noted indicia. For example, in at least one particular embodiment,holding member 212 could have both a different color and have adifferent tactility to that of carrier member 200.

Holding member 212 may be configured to be manipulated by either or boththe fingers of a surgeon as well as by suitable surgical tools. Suchtools include, but are not limited to, forceps or tweezers, hooks,clamps and suction tools, and others now or later developed. Such aconfiguration ensures that carrier member 200 may be used by any surgeonirrespective of whether that surgeon prefers to handle the carriermember by hand or with a tool during an implantation procedure. Itshould also be appreciated that the configuration of holding member 212may be such that it is suitable for a particular application, surgicalprocedure, application and the like.

Embodiments of the depicted carrier member 200 may also be insertableusing an insertion tool (not shown). Such an insertion tool supportscarrier member 200 and assists in delivering electrode array 205 of thecarrier member to the insertion location. One insertion toolparticularly well-suited for use with certain embodiments a carriermember of the present invention is described in InternationalApplication No PCT/AU03/00229, which is hereby incorporated by referenceherein. Such embodiments of the present invention are directed toensuring that the carrier member is shaped in such a manner where thecarrier member may easily be adapted for use with such a tool. FIG. 5 isa perspective view of a insertion tool cartridge 500 of the above-notedinsertion tool. In the embodiment illustrated in FIG. 5, support member214 is configured to extend through a slot 502 in cartridge 500 whencarrier member 200 is placed within the tool. Such an arrangementresults in carrier member 200 being operatively installed in theinsertion tool with support member 214 extending through slot 502, andthe remaining portion of holding member 212 being located external tothe cartridge. Such an embodiment facilitates the implantation of anelectrode array 104 that is electrically connected to simulator unit 106via lead 108 with no electrical connectors therebetween.

In certain embodiments, holding member 214 may have one or more featuresthat facilitate the grasping of carrier member 200 during, for example,the insertion of stylet 216 in lumen 226, or the installation of carriermember 200 into cartridge 500. Such additional grasping tool interfacefeatures may include, for example, an aperture 504 extending laterallythrough holding member 214, a pair of opposing indentations on opposingsides of holding member 214, etc.

The implantation of a carrier member such as carrier member 200 isdescribed next below. Carrier member body 202 is formed from aresiliently flexible material. Carrier member 200 has a substantiallystraight configuration prior to implantation or insertion through acochleostomy. Following completion of implantation, carrier member 200adopts a spirally curved configuration that matches the spiral nature ofthe scala tympani of the human cochlea. Carrier member 200 is preferablypre-formed with a spiral configuration and is then straightened eitherduring manufacture and packaging of the device or prior to implantation.

As depicted in FIG. 2, carrier member 200 may receive a stiffeningelement such as stylet 216 that is adapted to bias body 202 of carriermember 200 into at least a substantially straight configuration prior toand during initial insertion of carrier member 200 through thecochleostomy. The implementing stiffening element is preferably formedfrom a non-bioresorbable material such as a metal or metallic alloy. Forexample, in one embodiment, stylet 216 is made of platinum.

Stylet 216 is received in a lumen 226 within body 202 of carrier member200. Lumen 226 extends from an opening at proximate end 206 and extendsthrough body 202 to a location proximate distal end 222 of carriermember 200. Preferably, lumen 226 does not extend through holding member212. Stylet 216 may be positioned in lumen 226 during manufacture ofcarrier member 200 and serves to straighten carrier member 200 thatwould otherwise preferentially adopt a spirally curved configuration.

During use, distal end 222 of carrier member 200 is typically insertedinto the cochlea through a cochleostomy and is inserted firstly towardsthe first basal turn of the cochlea. During this initial procedure,stylet 216 preferably remains within carrier member 200 and is alsoadvanced into the cochlea. As such, there is preferably no relativemovement of carrier member 200 to stylet 216 during insertion of thecarrier member and up until distal end 222 is positioned at or near thefirst basal turn.

Once the surgeon has advanced the device to this position, stylet 216 isthen held in place as carrier member 200 is held at its holding member212 and then advanced relatively forwardly still further into thecochlea. As stylet 216 is held, the portion of carrier member 200adjacent distal end 222 slides forwardly off stylet 216. As this occurs,that portion of carrier member 200 begins to adopt its preferentialcurved configuration, causing distal end 222 to move further into thespiral-shaped scala tympani of the cochlea, preferably without strikingthe wall of the basal turn of the cochlea.

Once the electrode array 205 has been advanced the desired distance intothe cochlea, carrier member 200 may be held in place by holding holdingmember 212 as stylet 216 is withdrawn rearwardly out of lumen 226 andback out through the cochleostomy. By advancing carrier member 200 atleast partially off stylet 216, the leading portion of carrier member200 is free to start to adopt its preferential curved configuration andso enables the elongate carrier member to be inserted into the cochleain a way which minimizes, and preferably eliminates, trauma to the wallsof the cochlea.

On complete removal of stylet 216, elongate carrier member 200 is freeto adopt the fully curved pre-formed orientation along at least part ofits entire length and is so placed in its final position in the cochlea.

When implemented in connection with a cochlear prosthetic device,embodiments of the present invention assist a surgeon in performing acochlear implantation by identifying which portion of carrier member 200should be held during the implantation procedure if the potential fordamage to the member is to be minimized. The reduction in potential fordamage to the carrier member 200 should lead to an even lower rate ofimplant failure following implantation than hitherto has been the case.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive.

All documents, patents, journal articles and other materials cited inthe present application are hereby incorporated by reference. Althoughthe present invention has been fully described in conjunction withseveral embodiments thereof with reference to the accompanying drawings,it is to be understood that various changes and modifications may beapparent to those skilled in the art. Such changes and modifications areto be understood as included within the scope of the present inventionas defined by the appended claims, unless they depart therefrom.

1. An implantable tissue-stimulating prosthesis comprising: an elongatecarrier member having a distal end, a proximal end, and at least oneelectrode positioned thereon; at least one electrical conductorextending from one or more of the at least one electrode; a leadextending from the carrier member and enclosing the at least oneelectrical conductor; and a holding member constructed and arranged toradially extend outwardly from the surface of the carrier member tofacilitate grasping of the holding member during implantation of thecarrier member in a patient, wherein a carrier member tube comprises oneor more longitudinal and lateral slots on its surface, and wherein theholding member is mounted in the carrier member tube so as to beadjustable along the one or more longitudinal and lateral slots.
 2. Theprosthesis of claim 1, wherein the holding member is positioned adjacentto the proximal end of the carrier member.
 3. The prosthesis of claim 1,wherein the holding member is an elongate member that extendslongitudinally along a length of the carrier member.
 4. The prosthesisof claim 1, wherein the carrier member has a width; and wherein theholding member extends outwardly from the carrier member surface for adistance defining a height of the holding member.
 5. The prosthesis ofclaim 4, wherein the holding member has a width that tapers for aportion of its height away from the carrier member body.
 6. Theprosthesis of claim 1, wherein the holding member has a width thatvaries along its height to define vertical regions.
 7. The prosthesis ofclaim 1, further comprising: a support member that connects the holdingmember to the carrier member.
 8. The prosthesis of claim 7, wherein thesupport member has a width that is less than a maximum width of theholding member.
 9. The prosthesis of claim 1, wherein the holding memberis removably joined to the carrier member.
 10. The prosthesis of claim1, wherein the holding member is rotatably mounted to the carriermember.
 11. The prosthesis of claim 1, wherein the holding memberfurther comprises: an indicia that identifies the holding member on thecarrier member.
 12. The prosthesis of claim 1, wherein the holdingmember is constructed and arranged to be manipulated by the fingers of asurgeon.
 13. The prosthesis of claim 1, wherein the holding member isconstructed and arranged to be manipulated by a surgical tool.
 14. Theprosthesis of claim 1, wherein the tissue-stimulating prosthesis is acochlear implant system.
 15. An implantable tissue-stimulatingprosthesis comprising: an elongate carrier member having a distal end, aproximal end, and at least one electrode positioned thereon; at leastone electrical conductor extending from one or more of the at least oneelectrode; a lead extending from the carrier member and enclosing the atleast one electrical conductor; and a holding member constructed andarranged to radially extend outwardly from the surface of the carriermember to facilitate grasping of the holding member during implantationof the carrier member in a patient, wherein the holding member furthercomprises an indicia that identifies the holding member on the carriermember.
 16. The prosthesis of claim 15, wherein the indicia comprisestactility of the holding member.
 17. The prosthesis of claim 15, whereinthe indicia comprises a relative shape of the holding member and thecarrier member.
 18. The prosthesis of claim 15, wherein the indiciacomprises a color of the holding member.
 19. The prosthesis of claim 15,wherein the holding member is positioned adjacent to the proximal end ofthe carrier member.
 20. The prosthesis of claim 15, wherein the holdingmember is an elongate member that extends longitudinally along a lengthof the carrier member.
 21. The prosthesis of claim 15, wherein thecarrier member has a width; and wherein the holding member extendsoutwardly from the carrier member surface for a distance defining aheight of the holding member.
 22. The prosthesis of claim 15, whereinthe holding member has a width that varies along its height to definevertical regions.
 23. The prosthesis of claim 15, further comprising: asupport member that connects the holding member to the carrier member.24. The prosthesis of claim 15, wherein the holding member is removablyjoined to the carrier member.
 25. The prosthesis of claim 15, whereinthe holding member is rotatably mounted to the carrier member.
 26. Theprosthesis of claim 15, wherein a carrier member tube comprises one ormore longitudinal and lateral slots on its surface, and wherein theholding member is mounted in the carrier member tube such that theholding member is adjustable along the one or more longitudinal andlateral slots.
 27. The prosthesis of claim 15, wherein the holdingmember is constructed and arranged to be manipulated by the fingers of asurgeon.
 28. The prosthesis of claim 15, wherein the holding member isconstructed and arranged to be manipulated by a surgical tool.
 29. Theprosthesis of claim 15, wherein the tissue-stimulating prosthesis is acochlear implant system.